Retrospective Radiation Dosimetry Using Optically Stimulated Luminescence in Dental Enamel: Possibilities for In vivo Dosimetry
B. Pass, D. I. Godfrey-Smith, P. Scallion
Currently, retrospective radiation dosimetry in humans lacks a technique that is sensitive, non-invasive, and portable. Without the ability to randomly sample and measure exposure in the general population it is difficult to establish reliable cause and effect relationships between radiation exposure and resulting human detriment. Since optical technology is amenable to miniaturization, a search for optically stimulated luminescence (OSL) in dental enamel was begun. A time dependent OSL has been observed under IR and green photon stimulation in gamma irradiated samples of deproteinated human dental enamel. GSL was absent in samples that had not been irradiated or had been heated to 450°C after irradiation. Re-irradiation after heating caused a reappearance of the luminescence. OSL in deproteinated enamel can be useful for retrospective dosimetry when extracted teeth are available. OSL was also readily observed under IR photon stimulation in gamma irradiated samples of human dental enamel that had not been deproteinated. It is this effect which is relevant to in vivo dosimetry. If, in future studies, GSL can be detected in natural dental enamel, it too may be useful for in vivo dosimetry. A persistent dose dependent IRSL signal is also generated in deproteinated enamel that has been heated to 450°C. OSL of dental enamel can become the first non-invasive, simple, reliable, and portable means of retrospective radiation dosimetry in humans. Presently, possible obstacles to achieving this goal include low sensitivity, difficulty normalizing dose, signal fading, variation in opacity of enamel and in sensitivity to radiation which can make it difficult to calibrate dose and establish a dose response curve.
This abstract was presented at the 36th Annual Midyear Meeting, "Radiation Safety Aspects of Homeland Security and Emergency Response", Biophysical and Biological Techniques for Retrospective Radiation Dosimetry Session, 1/26/2003 - 1/29/2003, held in San Antonio, TX.